A prefabricated and unfilled side-gusset bag typically has front and back two face panels and two folded side panels that are each joined to the face panels at side edges and that each have a crease running in a bag longitudinal direction in the center between the respective side edges. A handle assembly has a film handle attached to one of the folded side panels on an outer side of the bag. This handle assembly further has longitudinally spaced handle ends and a handle middle section between the handle ends that extends transversely, i.e. perpendicular to the longitudinal direction, over less than 80% of the width of the respective folded side panel and has a spacing of at least 5 mm from each of the two respective side edges.
Side-gusset bags are used in various sizes for packaging purposes and are suitable, for example, as packaging for bulk goods such as dry feed for animals, detergent, cat litter, salt and powdery or grainy construction materials.
Such side-gusset bags are often also provided with a reclosable fastener in order to enable a certain level of protection after initial opening and removal of a partial quantity.
Such a reclosable fastener is usually arranged on a bag top or at least one upper region of the bag and can extend only over a part, for example a folded side panel, or the entire width. The reclosable fastener can be embodied, for example, as a so-called zipper or slide closure having rail-shaped groove and spring elements that can be closed manually by pressure in the case of a zipper closure or, in a slide closure, by a slide in the manner of a zipper, and opened through application of force in the opposite direction. Other reclosable fasteners, such as hook-and-loop fasteners or self-adhesive strips, for example, are also worthy of consideration.
Various manufacturing methods are known for the manufacture of side-gusset bags. For instance, the entire side-gusset bag can be formed by folding from a single film web. Both individual prefabricated side-gusset bags and side-gusset bags that are not yet sealed on at least one edge can be formed that are first stored and transported and then filled and sealed only later. One advantage of such pre-made bags is that relatively low equipment costs are involved. The prefabricated side-gusset bags are opened and then filled via a filling funnel before they are sealed by welding, adhesion and/or folding-over of the open section. The sealed side-gusset bag generally ensures tight storage of the filled product.
It is also possible to form individual bags using a so-called FFS (form fill and seal) method from a continuous film immediately during filling. To do this, a film tube with folded side panels is formed directly around a filling funnel that is then sealed immediately after filling, individual bags also being separated from the strip.
However, the present invention also relates to embodiments in which the face panels and the folded side panels are formed from separate pieces of a bag film.
U.S. Pat. No. 7,331,917 describes a method of making side-gusset bags in which a strip of bags is formed such that successive side-gusset bags are arranged with their bag longitudinal edges next to each other. The direction of production thus corresponds to a bag transverse direction of the individual side-gusset bags. According to U.S. Pat. No. 7,331,917, a strip of bags is first formed with successive, initially connected bag blanks. A first film web is guided in the direction of production. A film strip is then fed in, the edges of the film strip being folded over onto a middle section. The edges are usually of equal width, and a gap still remains between the two edges after folding.
Pieces of the film strip are then placed onto the first film web at a uniform spacing transverse to the direction of production (i.e., along the bag longitudinal direction) before a second film web is fed in the direction of production with which the first film web and the pieces of the film strips are covered. Longitudinal welds are then produced transverse to the direction of production with which the film strips are welded at the folded-over edges to the second film web on the one hand and welded at their opposite edge to the first film web on the other hand. Finally, individual side-gusset bags are separated from the strip of bags formed in this way by a cut in the region of the film strips such that two folded side panels of successive side-gusset bags are formed from one folded film strip. The described method is also referred to in practice as a transverse method or Totani method.
Independently of the method of making the side-gusset bag, a need often exists to provide the side-gusset bag with a handle assembly, such a handle assembly being on a bag top or on one of the two folded side panels.
The present invention relates specifically to a side-gusset bag with a handle assembly that is attached on the outside of the bag to one of the two folded side panels, the handle assembly having a film handle and being connected to handle ends when seen longitudinally, a handle section being located between the handle ends. The user's hand can then be passed between the handle section and the underlying folded side panel.
The entire handle assembly extends transversely, i.e., perpendicular to the longitudinal direction, over less than 80%, preferably less than 60% of the width of the respective folded side panel between the side edges, the handle assembly also having a spacing of at least 5 mm, preferably at least 15 mm from each of the two respective side edges.
Generic side-gusset bags are known in practice in which a single straight film strip with self-adhesive handle ends is applied to one of the folded side panels. To ensure a uniform weight distribution, such a film strip is arranged as a handle assembly transversely in the center, i.e., along the crease of the side edge. However, this leads to the corresponding folded side panel being spread open to a certain extent by the handle assembly when laid flat. This spreading effect renders storage and handling of prefabricated, unfilled side-gusset bags difficult. It must also be considered here that a relatively thick film is usually used for the handle assembly that is able to carry the entire side-gusset bag.
Against this background, difficulties also arise with FFS side-gusset bags with a glued-on film strip as a handle.
A generic side-gusset bag is known from WO 2009/095806 in which a weakening line can be provided in the film handle in order to enable easier folding of the side edge in the region of the handle assembly. Particularly with a thick film handle, however, a substantial tendency to spreading still remains.
Moreover, handle assemblies of other types are also known from the prior art. For instance, EP 2 039 620 describes a handle assembly with a film strip running transversely that is attached at the side edges.
U.S. Pat. No. 8,597,168 discloses a handle assembly with two loop handles that are each arranged at a side edge. Even though handling is rendered especially comfortable by the described design with two loop handles, manufacturing is relatively expensive.
A side-gusset bag with a handle on a folded side panel is known from U.S. 2011/0033133. Besides simple glued-on handle assemblies, other handle assemblies are described that have at least one film slip on the inside of the bag. Here, too, one encounters the limitation of relatively expensive manufacturing, and a substantial spreading effect is also observed depending on the design.